Vehicular battery pack

ABSTRACT

A vehicular battery pack comprising a parallelepiped-shaped container, wherein cells are arranged in layers one above the other in the container, and wherein relative monitoring devices of the individual cells are arranged on a second lateral wall, perpendicular to said layers and first lateral walls, perpendicular to said layers and to said second lateral wall, wherein said first lateral walls are configured to cool said layers of cells.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority from Italian Patent ApplicationNo. 102018000002771 filed on Feb. 16, 2018, the entire disclosure ofwhich is incorporated herein by reference.

FIELD OF APPLICATION OF THE INVENTION

The present invention refers to the field of energy storage systems inthe automobile sector and in particular to a battery pack comprising aplurality of electrically interconnected batteries.

DISCUSSION OF THE PRIOR ART

Because of their high density, lithium batteries are enabling theeffective implementation of electric technology in the automobilesector.

Lithium polymers currently represent the state of the art in theproduction of high-capacity batteries.

A known solution envisages the use of small cylindrical batteriesconnected in series in strings. One or more strings are then connectedin parallel to obtain voltage and current values compatible with theinverter that drives the electric traction motor. This solution resultsin a lot of unused space and the energy density could therefore beimproved.

Solutions are known which envisage the production of cells specificallydeveloped for use in the automobile sector, in which the cells arestacked, without casing, one on top of the other. Production costs aretoo high and the reliability of the battery pack is not assured.

The battery modules usually available on the market to power smartphonesand tablets consist of flat-pouch batteries, which have a very smallthickness in relation to their other dimensions. Such batteries have twovery wide opposite faces through which the heat is almost entirelydissipated and four thin and elongated sides with the positive andnegative terminals of the cell arranged on one or on two opposite sides.

Each module comprises a cell and a relative BMC (battery managementcontrol) monitoring device to monitor different operating parameters ofthe battery and disconnect it if necessary for safety reasons and/or toprotect the actual battery.

The various BMC devices of the battery pack are then connected as slavesto a so-called BMS (battery management system) which, as master,processes the information acquired by the BMC devices and interacts withthe vehicle unit, generally the VCU (vehicle control unit) that controlsvarious vehicle sub-systems, including the battery pack.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a vehicular batterypack based on conventional individual cells of the flat-pouch type inwhich the terminals are arranged on opposite sides of the cell.

The idea at the basis of the present invention is to group the cellstogether in layers at the centre of the battery pack, the relative BMC(battery management control) devices are arranged to form a secondlateral wall, perpendicular to said layers, and first lateral walls,perpendicular to said layers and to said first lateral wall, have thepurpose of cooling the layers of cells.

In other words, the vehicle unit, the cooling walls and the layers ofcells lie on mutually perpendicular planes.

More in particular, the battery pack has a parallelepiped-shapedcontainer in which the first lateral walls, arranged opposite oneanother, have the purpose of cooling down the cells and second twolateral walls, arranged opposite one another, have the purpose,

one of housing said vehicle unit including the BMC devices and a BMS(battery management system) that oversees the operation of the BMCdevices, andthe other of housing the high-voltage connections and the relativesafety devices.

The last two lateral walls that complete the parallelepiped, oppositeone another and parallel to the layers of cells, principally have thefunctions of containing and compressing the layers of cells.

Since the first walls and the second walls are connected to one another,the first walls have a dual function, that is, a structural function andthe function of cooling the cells.

Therefore, the BMC devices are not inside the pack with the respectivecells they control. This fact advantageously allows only the cells to becooled, thus optimising the volume inside the battery pack.Nevertheless, with the battery pack according to the present inventionthe condition and operation of each individual cell can be monitored.

A first layer of cells is fixed to a face of a planar tray and twoopposite edges of the planar tray are physically and thermally incontact with said first two lateral cooling walls of the container so asto transmit any heat generated by the cells to said first two lateralwalls. Preferably, each layer of cells defines an alignment of cells andon each opposite side of each cell facing an adjacent cell there is aterminal of that cell in order to be able to connect said alignments ofcells in series.

A flat cable is attached to one face of the tray interposed between saidface of the tray and a respective alignment of cells. Said flat cableoperatively interconnects the cells of said alignment to a BMC device,preferably a multi-channel device.

A flat cable generally comprises a substrate of plastic material onwhich metal tracks are arranged, using methods known in the prior art.

Advantageously, the fact that the BMC device is not included in the packwith a relative cell enables the use of one BMC device capable ofmonitoring the condition of two or more cells of a same layer andpreferably of two adjacent layers.

Preferably, the tray supports two alignments of cells each connected toone of the opposite faces of the tray and the same flat cable servesboth alignments of cells through appropriate openings provided in thetray.

According to a preferred embodiment of the invention, at the terminalsof each cell, the tray comprises a through opening, engaged by a supportof insulating material to which a band of metal is attached that iscompatible to be welded to the terminals of adjacent cells.Advantageously, the support performs several functions:

it insulates the terminals of the cells from the relative tray,it simplifies the interconnection of the cells,it allows said flat cable to be connected to the terminals of the cells.

According to a preferred embodiment of the invention, the alignmentsdefined by each layer of cells arranged in the battery pack are mutuallyinterconnected in series, so that all of the cells of the battery packare in series. Clearly, a head cell, that is to say, a cell proximal toone of said second walls, is electrically connected to another head cellof an adjacent alignment. Said adjacent alignment may be supported bythe same tray or by an adjacent tray.

In the first case, when the layers have been arranged in the batterypack, before fitting the second walls, a U-shaped bridge is used tomutually connect the terminals of the head cells of a same edgeconnected to opposite faces of a same tray. Vice versa, when the headcells belong to different trays, two L-shaped half-bridges are used andconnected to one another.

The claims describe preferred embodiments of the invention and form anintegral part of the present description.

BRIEF DESCRIPTION OF THE DRAWINGS

Further purposes and advantages of the present invention will becomeclear from the following detailed description of a preferred embodiment(and alternative embodiments) thereof and from the accompanying drawingswhich are merely illustrative and not limiting, in which:

FIG. 1 is a schematic side view of a battery pack according to thepresent invention;

FIG. 2 is a three-dimensional exploded view of an example ofimplementation of the present invention;

FIG. 3 is an exploded view of a portion of the example shown in FIG. 2;

FIGS. 4 and 5 are portions of longitudinal sections of the portion shownin FIG. 3 in assembled conditions according to FIG. 2;

FIGS. 6 and 7 are enlarged views of details of FIG. 3;

FIGS. 8A, and 9A are portions of a cross section of the example shown inFIG. 2 and FIG. 8B is an enlarged view of a portion of FIG. 8A;

FIG. 9B shows a portion extracted from FIG. 9A;

FIGS. 10 and 11 compare two alternative embodiments of a detail of FIG.2;

FIG. 12 is an exploded view of the components that form a wall of thecontainer according to the present invention;

FIG. 13 is a plan view of the wall shown in FIG. 12 seen from inside thebattery pack according to the example illustrated in FIG. 2;

FIG. 14 is a view from above of a portion of the battery pack showing awall opposite the wall shown in FIGS. 12 and 13;

FIG. 15 is a quasi-cross-sectional view along the line AA of FIG. 14;

FIG. 16 is a partially exploded view in perspective of the wall shown inFIG. 14.

In the figures the same reference numerals and letters indicate the sameparts or components.

Within the scope of the present description, the term “second” componentdoes not imply the presence of a “first” component. Such terms aresimply used for the sake of clarity and should not be considered aslimiting the scope of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

FIG. 1 is a schematic side view of a battery pack BP according to thepresent invention. This view is perpendicular to first mutually oppositelateral walls S1 (S1.1 and S1.2) of the parallelepiped-shaped containerthat contains the cells C which define the battery pack.

Said first walls define a first pair of walls, in that they are parallelto one another and arranged opposite one another to define the batterypack.

The concept of “pair” also applies to the other walls S2 and S3described later on in this document. The cells C have a more or lessplanar shape and are arranged inside the container so as to beperpendicular to the first lateral walls S1, so that said side view inFIG. 1 shows said cells from the side.

The expression “more or less planar” means that the thickness of thebatteries is many times smaller than the other dimensions thereof.

FIG. 1 is a schematic illustration of mutually opposite second wallsS2.1 and S2.2, which too are perpendicular to the planar development ofthe cells C and perpendicular to the walls S1.1 and S1.2 perpendicularto the view direction of FIG. 1.

The walls S1, S2 and S3 that make up the battery pack are more or lessplanar.

Considering a plane parallel and intermediate to said first walls S1,these are structurally symmetrical with respect to said intermediateplane. This is because coils, that is to say, ducts through which acooling liquid flows, are housed inside the first walls S1.

The second walls are indicated using different symbols, because they arenot structurally symmetrical, in that the first S2.1 of the second wallsS2 defines a housing for the electronic monitoring and control devicesBMC/BMS of the cells, while the second S2.2 of the second walls is madeup of high-voltage electrical components to guarantee the intrinsicelectrical safety of the battery pack.

Thus, the vehicular battery pack BP comprises a parallelepiped-shapedcontainer, wherein cells C are arranged in layers L arranged one abovethe other in the container, and wherein relative monitoring devices BCMof the individual cells are arranged on the second lateral wall S2.1,perpendicular to said layers L and to the first lateral walls 1,perpendicular to said layers L and to said second lateral wall S2.1,wherein said first lateral walls are configured to cool said layers ofcells.

Each layer may comprise several cells, for example three, and the cellsof each layer are connected to one another in series.

The various layers that make up the battery pack may form a singleseries connection or they may be connected to form two or more parallelconnections of series connections. This clearly depends on the voltageand current to be operationally generated by the battery according tothe characteristics of each cell C.

The batteries must be appropriately cooled. This is achieved by means ofappropriate trays T made of metal material that drains the heat from thecells and transfers it to the first lateral walls. Therefore, the traysgenerally have a planar shape and the opposite edges of the tray, facingthe lateral walls S1, are shaped so as to contact and transfer heat tosaid first walls S1.

To achieve the best heat exchange between the cells and the trays, thecontact between the cells and said trays is direct. A layer ofconductive grease could be applied between the cells and the respectivetrays in order to promote the exchange of heat.

A layer of cells is mechanically and thermally connected to said tray.

Each of said layers of batteries is preferably connected to a face of atray T by means of the relative terminals C+ and C− of said cells.

The positive terminals C+ and negative terminals C− are preferablyarranged on opposite sides of each cell according to a direction Xperpendicular to the second walls S2 (S2.1 and S2.2).

The axis X of FIG. 2 indicates the direction of the longitudinalextension of the trays and therefore of the entire battery pack.Therefore, FIGS. 8A, 9A, and 9B are cross sections of said longitudinalextension.

Each tray T comprises a housing H, HH and a support B, HB1, HB2 ofinsulating material suitable to complementarily engage said housing,wherein said support comprises a first band of metal material MB, MB1,MB2 attached to a face of the support and appropriately insulated fromsaid tray, so that, in operating conditions, a terminal C+, C− of atleast one cell C is welded to said band of metal material, so that saidat least one cell is attached to a relative tray by means of saidrelative support B, HB1, HB2.

In other words, the cells are attached to the respective trays by theirterminals, so that the body of the cells and the relative trays are indirect contact. The conductive grease does not in any way serve to blockthe cells on the trays.

Thanks to the solution involving the use of such insulating supports, acell can be connected quickly to a relative tray, while at the same timeensuring the electrical insulation between the terminals of the cell andthe tray that is made of metal material to fulfil the aforesaid purposesof draining heat.

As shown in the figures, the cells have a planar extension and define afairly pronounced rectangular footprint. Therefore they define alongitudinal albeit planar extension. They are arranged so as to bealigned according to the axis X described above.

According to a preferred embodiment of the present invention, the layersare organised in alignments of cells aligned according to saidlongitudinal extension, therefore the battery pack, if made up of asingle alignment for each layer, also has a pronounced longitudinalextension.

The alignments are indicated by the symbols V1, V2, etc. The terminalsC+, C− are arranged on the (short) sides of each cell and face anothercell of the same alignment, forming a vector.

Thus the cells of an alignment are connected to one another in seriesand each cell has respective terminals C+, C− arranged on opposite sidesof said cell, and the terminals of two adjacent cells are welded to saidfirst band of metal material MB. In that case the support is referred toas an “intermediate support”.

Said housing H preferably consists in a through opening obtained in thetray, and the support is substantially flat with two opposite facesthat, once it has been inserted in the housing, face the opposite facesof the tray.

The first metal band MB1 is attached to the first face of the support ofinsulating material and a second metal band MB2, insulated from saidfirst metal band and from said tray, is attached to the second face,opposite the first face. Thus, advantageously, a first alignment ofcells V1 could be connected to a face of said tray T and a secondalignment of cells V2 could be connected to an opposite face of saidtray.

Advantageously, a second alignment of cells V2 is connected to anopposite face of said tray and adjacent terminals of cells of said firstalignment are welded to said first metal band MB1 and adjacent terminalsof cells of said second alignment are welded to said second metal bandMB2, preventing said support from disengaging from said respectivehousing.

According to a preferred embodiment of the invention the support furthercomprises a lateral housing LH suitable to receive and permanentlysupport an electric connector PC of a flat cable FC and said connectorcomprises a first electrical port STP for connecting to it a metalterminal ST suitable, in operating conditions, to interconnect saidfirst metal band ST to said first electrical port STP. Since the voltagecan be measured at all the terminals, the voltage of each cell can bemeasured.

When two alignments V1, V2 of cells are connected to a first and asecond face, opposite said first face, of said tray T, said lateralhousing LH preferably consists in a through opening suitable topermanently receive said electric connector PC so that a secondelectrical port is accessible from said second face and can be connectedto said second metal band by means of a relative corresponding metalterminal.

Advantageously, the same flat cable FC interconnects both of thealignments of cells V1 and V2 arranged on the opposite faces of a sametray.

The tray T which has a substantially rectangular shape has end housingsHH, preferably, cuts. Connected to each housing there is a relativesupport HB1 and HB2 of insulating material, defined here as end supportsHB1 and HB2, similar to the intermediate supports described above, butwith specific features bearing in mind that they must interconnect onealignment with another alignment and not simply two adjacent cells of asame alignment.

Also in this case an end support comprises a first band of metalmaterial MB1 attached to a face and appropriately spaced from said tray,so that, in operating conditions, the terminal C+, C− of at least onehead cell C is welded to said band of metal material. For the sake ofsimplicity, the same symbols and reference numerals are used to indicatecomponents that have the same functions.

When the support of metal material HB1 is used to interconnectalignments of cells connected to two different trays, the first metalband BM1 has an L-shaped section according to a plane perpendicular tosaid tray and according to the direction X, when in operatingconditions, so as to allow the electrical connection to an identicalmetal band of a head cell, of an adjacent layer of cells, connected toanother tray.

Vice versa, when the two alignments to be interconnected are connectedto opposite faces of the same tray, the series connection is achieved bymeans of a U-shaped metal band MB, see FIG. 5, engaging said support ofinsulating material HB2 so as to face opposite faces of the support ofinsulating material and short-circuiting the end terminals of the cellsconnected to the opposite faces of the same tray.

When all the layers of cells are interconnected by means of theintermediate and head support elements, then all of the cells of thebattery pack are in series and therefore the voltage measured at theterminals of the battery pack is equal to the sum of the voltages of allthe cells. Thus the free terminals of the head and tail cells areconnected to two corresponding busbars inside the battery pack.

The support of insulating material further comprises a lateral housingLH, similarly to the intermediate support, suitable to receive andpermanently support an end electric connector PC of the flat cable FC.The connector preferably comprises a temperature sensor TSS thatlaterally protrudes, so as to contact a relative cell.

The sensor TSS is preferably interposed between two head cells connectedto opposite faces of the same tray T. In particular, the sensor isarranged between the terminals of the same cells, which are the hottestpoints. Temperature sensors may also be connected to the electricconnectors supported by the intermediate supports described above.

The monitoring devices BMC of the individual cells are connected to theterminals of the cells by means of the aforesaid flat cable FC attachedto a face of said tray T interposed between said layer of cells and saidtray.

As already mentioned, each of the first lateral walls S1 comprises acooling liquid circulation circuit, integrated in the wall, and arelative inlet IN and outlet OUT, so that the inlets and the outlets ofboth of the first walls S1.1 and S1.2 are arranged at the corners ofsaid second wall S2.1 with openings having axes perpendicular to a planedefining said second wall S2.1 and preferably the relative coolingcircuits are connected in series by means of an outer duct PP, so thatan inlet IN of the series-circuit, that is to say, of the circuit formedby the series of the circuits contained in the two first lateral walls,and an outlet OUT of the series-circuit are at the consecutive cornersof said second wall S2.1 or at opposite corners of said second wallS2.1.

By arranging the cooling circuits laterally with respect to eachalignment and connecting only one alignment to each face of the trays,each cell is always subject to the same heat exchange power.

Let us assume that the temperature at the inlet is 50° C. and thetemperature of the liquid at the outlet of the first circuit is 75° C.and the temperature at the outlet of the second circuit is 100° C.

With the arrangement shown in FIGS. 1 and 10, the cells of the highesttray feel 50° C. on one side and 100° C. on the other. Whereas the cellsof the lowest tray feel 75° C. on both sides, which is equal to theaverage value felt by the cells of the highest tray.

This however means the highest cells have to be used with a highertemperature gradient on opposite sides.

With the solution shown in FIG. 11, in which the outer duct is arrangedobliquely, the cells of the highest tray feel 75° C. on one side and100° C. on the other. Whereas the cells of the lowest tray feel 50° C.on one side and 75° C. on the other side. This means that not only arethe cells subject to the same heat exchange power, but also to the samedifference in temperature between the opposite sides, which may beuseful in relation to the characteristics of the cells used. However,this means that the cells are only subject to uniform heat exchange ifthere is a difference in temperature between the first and the lastlayer. In the example, this difference in temperature is 25° C.

Therefore, the first walls have both a thermal and a structuralfunction, as they allow the interconnection of the other walls of thecontainer that form the aforesaid parallelepiped, especially the thirdwalls S3 which are designed to compress the layers between them. Duringthe charging process, the cells tend to dilate perpendicularly inrelation to the faces, whereas during discharging, they tend tocontract. The compression of the cells, perpendicularly to the relativefaces, promotes the contraction of the cells.

Therefore, the lateral walls S1.1 and S1.2 have the function of coolingthe battery pack and are dimensioned to withstand a traction forcebetween the third walls S3.1 and S3.2 which compress the layers of cellsC. Another purpose of the present invention regards a specific form ofeach tray.

FIGS. 8A and 9A illustrate cross sections of a plurality of trays.

As can be seen, although the tray is generally flat, it is provided withlateral edges, designed to come into contact with the two thicker firstwalls S1. Each edge, in a sectional view, approximates a Y shape withthe divergent ends of the Y joined by a straight segment.

Said straight segment defines, three dimensionally, a heat exchange wallof the tray with the two first walls S1. The divergent ends, instead,have several functions:

-   -   they double the section of the heat dissipation path; the heat        dissipated by the (largest) faces of the cells must be conveyed        and transferred to the first walls S1, therefore, thanks to the        present solution, the thermal resistance of the tray is reduced        up to said straight segment that defines the surface of        interaction or interface, with the first walls S1. Said straight        segment has an extension which clearly cannot exceed the        thickness of two alignments of cells and of the actual tray,        otherwise the packing effect deriving from the mutual contact        between the cells of due alignments of cells connected to two        consecutive trays would be lost;    -   defined between the divergent ends of the Y-shaped section and        said straight segment there is a longitudinal duct according to        X, that may have any cross section: triangular, circular,        rectangular, which on the one hand makes the tray lighter, while        achieving the purposes disclosed in the previous point, and also        allows the insertion of electric wires and various sensors to        connect temperature sensors or to measure the voltage at the        individual cells, as well as the installation of temperature        sensors or, for example, an accelerometer;    -   they contain the cells connected to the opposite faces of the        tray, preventing said cells from being damaged as a result of        the compression force exerted by the third walls S3 thanks to        the support of the second walls S2; and they prevent any        crosswise displacement of the cell with respect to the relative        tray in the case of a collision.

Said duct defined between the divergent ends of the Y shape does nothave the function of circulating liquid, in that the liquid circulatesentirely inside the lateral walls S1. As described above, the cells arepreferably attached to the tray by means of the terminals on the actualcell and the supports described above. Clearly, the main purpose ofthese is electrical, although they are sufficient to keep the cellsconnected to the relative tray during the assembly of the battery pack.

During an accident, accelerations could be such as to cause the supportsto break if put under excessive stress. The very shape of the trays,which complements the parallelepiped shape of the cells, is such toblock them inside the relative tray.

Advantageously, no adhesive is required to secure the cells to the tray.

FIG. 9B is a detailed view of a cross section of one S3.1 of the wallsS3. It is shaped, as described above, to exert a uniform compressiveforce on the layers of cells. According to the section in FIG. 9B, itresembles a trussed arch, in which a longitudinal groove CL is obtainedto house electric cables W. Said groove is accessible from the outside,after said wall has been connected to the first lateral walls S1.

As described above, the purpose of one S2.1 of the second walls S2 is togroup together and enclose the monitoring devices BMC and BMS of thecells grouped together inside the battery pack.

The purpose of the opposite wall S2.2 is to group together and enclosesafety devices and high-voltage connections. Should one or more cellsoverheat, the monitoring devices must be able to act directly on thesafety devices, disconnecting the battery pack from the circuit outsidethe battery.

In that case, the monitoring devices work with the safety devicesarranged on the opposite side of the battery. This is achieved,according to a preferred embodiment of the present invention, byembedding the electric cables W in at least one S3.1 of the third wallsS.3.

The longitudinal groove CL is formed so as to be accessible from theoutside of the battery pack. Once the electric cables W have beenarranged in said groove, a cover CV is fitted, see FIG. 9B.

FIG. 12 is an exploded view of the first S2.1 of the second walls S2.

From left to right on the sheet there are a cover CV, the BMS thatsupervises the BMC devices configured as slaves, a frame FR forconnecting the BMS to the BMC devices.

The frame FR allows the BMS to be connected directly to the BMC deviceswhich therefore act as a support for the BMS. The connection between theBMS and the BMC is achieved with an open daisy chain-type serialconnection.

Therefore the BMC devices are connected in series to define slavedevices and the last BMC in the alignment shown in FIG. 13 is connectedto the BMS arranged behind said alignment.

The BMC devices, arranged side by side when in operating conditions,define a flat object.

The BMS is also flat and on it there is arranged an electric connectorfor connecting the BMS to a vehicle data network.

Furthermore, in the same Figure it can be noted that each BMC modulecomprises a pair of electric connectors BMCc for connecting to acorresponding pair of flat cables, each connected to a tray to controleach cell of both of the alignments of cells connected to the oppositefaces of each tray.

The second S2.2 of the second lateral walls S2, as mentioned above,includes electrical components, including high-voltage busbars, sensorsfor measuring the voltage and current of the entire battery pack andsafety devices, such as circuit breakers suitable to disconnect theelectricity supply when deemed necessary.

Said wall S2.2 is therefore formed by a casing that is more or lessparallelepiped in shape, in which said components are preliminarilyinstalled and comprises one or more external connectors PGE forconnecting the battery pack to the vehicle's high-voltage power supplysystem.

When the various electrical components are installed in this wall, theresulting assembly is called E-box EB in that it contains thehigh-voltage measurement and safety devices.

Said E-box is at least partially open towards the volume delimited bythe walls S1 and S2.

Said assembly of components further comprises two terminals TB1 and TB2,one positive and one negative, to be connected to corresponding busbarsBB1 and BB2 directly connected to the plurality of cells contained inthe battery pack.

Thus, the cells energise the busbars BB1 and BB2 and when the terminalsTB1 and TB2 are connected to the busbars they, in turn, are energised.

According to a preferred solution, the terminals TB1 and TB2 aresuperimposed on the corresponding busbars when the wall S2.2 is moved upagainst the first S1 and second pre-assembled walls S2.

Said superimposition brings respective holes into alignment.

Next, screws Scw1 and Scw2 are inserted through openings arranged inopposite faces of the parallelepiped defining the wall S2.2 topermanently connect the terminals TB1 and TB2 to the respective busbarsBB1 and BB2.

Alternatively, the mutual connection between the terminals and thebusbars can be achieved by means of pug/socket connections.

The busbars protrude in the direction of the second wall S2.2 to enterthe housing EB defined by said wall S2.2. When the wall S2.2 isconnected to the remaining battery pack each of the busbars can only beaccessed through one of the two openings arranged in opposite faces ofthe housing EB. Advantageously, enabling access to the busbars throughopposite faces of the parallelepiped defining the wall S2.2 guaranteesgreater safety for the operator during the assembly of the battery pack,preventing the possibility of short-circuiting the battery pack.

As shown in FIG. 16, between one busbar BB2 and the terminal TB2, theconnection is not direct, but indirect, via a fuse FSE that isaccessible through a specific removable door SV2.

Clearly, the wall S2.2 may have a different shape other than aparallelepiped, but without affecting the fact that the connectionsbetween terminals and the relative busbars must be accessible throughopposite faces of the container defining the wall S2.2 that encloses therelative high-power circuitry.

Furthermore, the fact that while one pair TB1/BB1 come into directcontact with one another when the wall S2.2 is moved up against theremaining pre-assembled battery pack, the other pair TB2/BB2 cannot comeinto contact until the high-voltage fuse FS2 has been fitted, isextremely advantageous as this prevents the unstable energising of anyof the sensors housed in the wall S2.2.

According to a further preferred embodiment of the invention, when thewall S2.2 is physically connected to the remaining battery pack, both ofthe terminals TB1 and TB2 of the E-box remain appropriately spaced fromthe busbars BB1 and BB2 towards which the connections of all the cellsconverge.

To interconnect a terminal with a respective busbar, a fuse must befitted which thus acts as a bridge. Also in this case the two fuses canbe accessed through openings in opposite faces of the E-box whichincreases the level of safety for the operator during the assembly ofthe battery pack.

When the wall S2.2 and the remaining battery pack have been mutuallyassembled, that is, when the perimeter screws illustrated in FIG. 16have been tightened and the pairs TB1/BB1 and TB2/BB2 have beenconnected by means of the fuse(s), the door(s) CV2 is(are) fitted and/ora cap Plg made of resilient material is inserted in the opening thatgives access to the pair BB1/TB1.

According to a preferred method of assembling the battery pack, thefirst walls S1.1 and S1.2 are connected to the third wall S3.2 and thetrays T, to which the cells have already been connected, are placedinside it.

Next, the BMC devices are connected to the respective flat cables, theyare connected in series as shown by the bridges in FIG. 13, and the BMSis arranged above them by means of the aforesaid frame FR, and the BMSis connected to one of the BMC devices.

At the same time, or before or afterwards, the wall S3.1 is alsoconnected to the first walls S1 and said cables W are housed therein,connecting them, by means of a relative end, to a specific connectorBMSc of the BMS.

Next, the pre-assembled E-box is brought close and the steps describedabove are performed, and another end of said cables W is connected to asecond electric connector EBc integral with the E-box. This step makesit possible to interconnect the BMS to the safety circuit breakersarranged in the E-box.

Next, the cover CV is fitted to complement said longitudinal groove.

Other embodiments of the non-limiting example of the invention describedherein may be implemented without departing from the scope of protectionof the present invention, including all the equivalent embodimentsimplemented by the person skilled in the art.

From the above description it will be possible for the person skilled inthe art to implement the invention without the need for any additionalconstruction details. The elements and the characteristics illustratedin the different preferred embodiments, including the drawings, may becombined without departing from the scope of protection of the presentapplication. That described in the discussion of the prior art servesmerely to ensure a better understanding of the invention and does notconstitute a declaration concerning the existence of that described.Moreover, unless specifically excluded in the detailed description, thatdescribed in the discussion of the prior art is to be considered asforming an integral part of the detailed description.

1. A vehicular battery pack (BP) comprising a parallelepiped-shapedcontainer, defined by pairs of first (S1), second (S2) and third (S3)lateral walls that are mutually perpendicular, wherein cells (C) arearranged in layers (L) one above the other in the container, and whereinrelative monitoring and supervision devices (BMC, BMS) of the individualcells are arranged so as to define a first (S2.1) of said second lateralwalls (S2), perpendicular to said layers (L) and wherein said firstlateral walls (S1), perpendicular to said layers (L) and to said secondlateral walls (S2), are configured to dissipate heat generated by saidlayers of cells.
 2. The battery pack according to claim 1, wherein eachof said layers of batteries is connected to a face of a tray (T),wherein each tray is parallel to said third pair (S3) of lateral walls,and wherein between a layer of batteries and a tray there is interposeda flat cable (FC) having a longitudinal extension (X) parallel to saidfirst walls, operationally connected to said monitoring and supervisiondevices (BMC, BMS).
 3. The battery pack according to claim 2, whereinsaid flat cable is arranged to interconnect terminals of the cells ofone layer to said monitoring and supervision device arranged in a firstof said second pair of walls (S2.1).
 4. The battery pack according toclaim 1 wherein each cell is connected to a respective tray throughterminals (C+, C−) of the same cells.
 5. The battery pack according toclaim 2, wherein said tray (T) generally has a planar shape and oppositeedges (T1, T2) shaped so as to contact and transfer heat to said firstwalls (S1).
 6. The battery pack according to claim 5, wherein said tray(T) comprises a housing (H, HH) and a support (B, HB1, HB2) ofinsulating material suitable to complementarily engage in said housing,wherein said support comprises a first band of metal material (MB)attached to a face of the support and appropriately insulated from saidtray, so that, in operating conditions, a terminal (C+, C−) of at leastone cell (C) is welded to said band of metal material, so that said atleast one cell is attached to a relative tray by means of said relativesupport (B, HB1, HB2).
 7. The battery pack according to claim 6, whereinsaid layers are organised in alignments (V1, V2), wherein each alignmentcomprises two or more cells mutually connected in series, with each cellhaving respective terminals (C+, C−) arranged on opposite sides of thesame cell, and wherein terminals of two adjacent cells are welded tosaid first band of metal material (MB).
 8. The battery pack according toclaim 6, wherein said housing (H) consists in a through opening whereinsaid support is substantially flat with two opposite faces, wherein saidfirst metal band (MB1) is attached to a first face and said second metalband (MB2) is attached to a second face, insulated from said first metalband and from said tray.
 9. The battery pack according to claim 7,wherein a first alignment of cells (V1) is connected to a first face ofsaid tray (T) and a second alignment of cells (V2) is connected to asecond opposite face of said tray.
 10. The battery pack according toclaim 8, wherein a first alignment of cells (V1) is connected to a firstface of said tray (T) and a second alignment of cells (V2) is connectedto a second opposite face of said tray and wherein adjacent terminals ofcells of said first alignment are welded to said first metal band (MB1)and wherein adjacent terminals of cells of said second alignment arewelded to said second metal band, preventing said support fromdisengaging from said respective housing.
 11. The battery pack accordingto claim 8, wherein said support further comprises a lateral housing(LH) suitable to receive and permanently support an electric connector(PC) of a flat cable (FC) and wherein said connector comprises a firstelectrical port (STP) for connecting to it a metal terminal (ST)suitable, in operating conditions, to interconnect said first metal band(MB1) to said first electrical port (STP).
 12. The battery packaccording to claim 11, wherein when alignments (V1, V2) of cells areconnected to a first and a second face, opposite to said first face, ofsaid tray (T), said lateral housing (LH) consists in a through openingsuitable to permanently receive said electric connector (PC) so that asecond electrical port is accessible from said second face and can beconnected to said second metal band by means of a relative correspondingmetal terminal.
 13. The battery pack according to claim 6, wherein saidhousing (HH) is at an end, in a position proximal to one of said secondlateral walls (S2), and a relative support (HB1, HB2) comprises a firstband of metal material (MB1) attached to a face and appropriately spacedfrom said tray, so that, in operating conditions, the terminal (C+, C−)of at least one head cell (C) is welded to said band of metal material.14. The battery pack according to claim 13, wherein said first metalband (MB1) has an L-shaped section, when in operating conditions andaccording to a plane perpendicular to said tray, in order to allow theelectrical connection to an identical and opposite metal band of anadjacent layer of cells, connected to an adjacent tray.
 15. The batterypack according to claim 13, wherein said tray has a first face and asecond face opposite to said first face and wherein a first layer ofcells is connected to said first face and a second layer of cells isconnected to said second face and wherein two head batteries of a sameedge of said tray belonging respectively to said first and second layerof cells are connected in series by means of a U-shaped metal band (MB)fitted to said support of insulating material (HB2) so as to be facingopposite faces of the support of insulating material corresponding toopposite faces of the relative tray.
 16. The battery pack according toclaim 13, wherein said support of insulating material further comprisesa lateral housing (LH) suitable to receive and permanently support anelectric connector (PC) of a flat cable (FC).
 17. The battery packaccording to claim 16, wherein said connector comprises a temperaturesensor (TSS) that laterally protrudes, so as to contact a relative cell.18. The battery pack according to claim 1, wherein said pair of thirdwalls (S3) are configured to compress said layers (V1, V2 . . . ) ofcells (C) according to a direction perpendicular to said layers andwherein said pair of first lateral walls (S1), configured to dissipateheat, are also arranged to structurally support said pair of secondlateral walls.
 19. The battery pack according to claim 13, wherein saidmonitoring devices (BMC) are physically supported by respective endsupports and wherein each BMC comprises at least one electric connector(BMCc) for said flat cable (FC).
 20. An electric or hybrid vehiclecomprising an electric motor connected to a vehicular transmission andcharacterised in that it comprises a battery pack according to claim 1.